Why changing to new cpu gen make a b350 boot?

I was trying to boot a b350 f gaming, but nothing worked, until I changed the r5 2600 for a r5 3500x, can someone explain why going to a "better" gen would be better for a old b350?, Btw the r5 2600 is working just fine is just weird that going up a gen fix the issue like I'm just confused, and somewhat pissed